Americans receive large amounts of dietary selenium, from 60 to 220 mcg/day. The recommended intake of selenium is just 55 mcg/day. The U.S. has high levels of selenium in the soil.
Selenium is needed for function of the enzyme, glutathione peroxidase. Glutathione peroxidase levels are not increased by raising serum selenium above 70-90 micrograms/liter. Any extra intake is stored as selenomethionine in plasma proteins. The risk of selenium deficiency in the U.S. is very small. The gap is narrow between a good selenium dose and the toxic dose for humans.
There is an association between high selenium levels and the risk of diabetes, hypercholesterolemia and hypertension. The present study was done to learn more about those associations. The authors studied a large sample of blood specimens from the U.S. population for fasting glucose and diabetes tests.
The patients were divided into four groups depending on their selenium blood levels. Ten percent of all the patients had diabetes, high fasting glucose and glycosylated hemoglobin.
The mean level of blood selenium was 137.1 micrograms/liter. The highest fasting blood sugar levels and glycosylated hemoglobin levels were seen in people with the highest selenium levels.
Previous studies have shown that the presence of excessive reactive oxygen species is associated with insulin resistance and can alter pancreatic beta cell activity. Previous studies have shown increased selenium levels with aging, also.
CONCLUSION: Increased incidence of diabetes is seen in patients with the highest levels of blood selenium. More research is needed to study the role of selenium in the progress of diabetes. Selenium supplementation raises the risk of diabetes in people who have an adequate intake of selenium.
NOTE: Selenium can be tested by toenail or hair
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